Add yaml swaglint linter (#771)

* Add yaml swaglint linter

doc/ale-yaml.txt

@@ -2,6 +2,40 @@
 ALE YAML Integration                                         *ale-yaml-options*
 
 
+===============================================================================
+swaglint                                                    *ale-yaml-swaglint*
+
+Website: https://github.com/byCedric/swaglint
+
+
+Installation
+-------------------------------------------------------------------------------
+
+Install swaglint either globally or locally: >
+
+  npm install swaglint -g  # global
+  npm install swaglint     # local
+<
+
+Options
+-------------------------------------------------------------------------------
+
+g:ale_yaml_swaglint_executable                 *g:ale_yaml_swaglint_executable*
+                                               *b:ale_yaml_swaglint_executable*
+  Type: |String|
+  Default: `'swaglint'`
+
+  This variable can be set to change the path to swaglint.
+
+
+g:ale_yaml_swaglint_use_global                 *g:ale_yaml_swaglint_use_global*
+                                               *b:ale_yaml_swaglint_use_global*
+  Type: |String|
+  Default: `0`
+
+  See |ale-integrations-local-executables|
+
+
 ===============================================================================
 yamllint                                                    *ale-yaml-yamllint*
 

doc/ale.txt

@@ -121,6 +121,7 @@ CONTENTS                                                         *ale-contents*
     xml...................................|ale-xml-options|
       xmllint.............................|ale-xml-xmllint|
     yaml..................................|ale-yaml-options|
+      swaglint............................|ale-yaml-swaglint|
       yamllint............................|ale-yaml-yamllint|
   6. Commands/Keybinds....................|ale-commands|
   7. API..................................|ale-api|
@@ -224,7 +225,7 @@ The following languages and tools are supported.
 * Vim help: 'proselint'
 * XHTML: 'proselint'
 * XML: 'xmllint'
-* YAML: 'yamllint'
+* YAML: 'swaglint', 'yamllint'
 
 ===============================================================================
 3. Global Options                                                 *ale-options*